// Load the Visualization API and the piechart package.
google.load('visualization', '1.0', {
    'packages':['corechart']
    });
      
// Set a callback to run when the Google Visualization API is loaded.
google.setOnLoadCallback(drawChart);

// Callback that creates and populates a data table, 
// instantiates the pie chart, passes in the data and
// draws it.
function drawChart() {
        
        
    // Create the data table.
    var data = new google.visualization.DataTable();
    data.addColumn('string', 'Topping');
    data.addColumn('number', 'Slices');
    data.addRows(
        [
        ['Mushrooms', 3],
        ['Onions', 1],
        ['Olives', 1], 
        ['Zucchini', 1],
        ['Pepperoni', 2]
        ]);

    // Set chart options
    var options = {
        'title':'How Much Pizza I Ate Last Night',
        'width':400,
        'height':300
    };

    // Instantiate and draw our chart, passing in some options.
    var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
    chart.draw(data, options);
}
